Will artificial intelligence make the human more rational?
I would counter this question with another one:
Is rationality all we strive for?

Intelligence is a waste ground, and we have not even defined which intelligence we're talking about: Emotional Intelligence (empathy), Rational/Intellectual Intelligence (IQ), artistic intelligence, etc. etc. etc.

Something which demarks us as humans is that sometimes we're able to deal with to counteracting intelligences. Logic sometimes dictates one thing, but logic is bound to what parameters are taken into account, and mostly it's about quantifying. an intelligence which does qualitative logic behaves sometimes different, and suggests sometimes other actions.
As humans we weight and counterweight these factors.

Politics is a good example. In most countries there are 2 or 3 rational approaches to problem solving (to make it easy let's call them left, center, right - though I know in fact it's more positions and in an at least two dimensional space, not linear).
But what I mean is all those positions are rational, nevertheless it's other types of intelligence who define their the way they use their ratio.

So in the end this fourth step is just a continuity and I assume that with time theoretically at least the shift should be away from blue collar jobs to more white collar jobs until there are no blue collar jobs.
So far the theory I guess, but then again? Would this be smart? Or intelligent? A world where machines make all the dirty work and we're just supervisors?

My thought to this is we will still need mechanics, probably with more technology always more, just that their focus will shift. 20 years ago mechanics were teached analogue technology, nowadays they learn more digital technology (best example would be car mechanics), but there you see: They're still needed, we also need people with analogue knowledge to mantain older systems which cannot or will not be converted to digital era. And I think that's OK!
So from my point of view, nobody has to fear to loose it's job, but instead embrace, that when you keep your knowledge up to date, there will always be a job for you.
Nowadays for example IT-professionals who are able to code older computer languages are better paid than ever, because their scarce...